"It was like a fingerprint; we found the culprit, and it was the nitrogen in the rocks," Morford said.
Implications for climate change:
The researchers stress that, since nitrogen tends to be elevated in rocks of sedimentary origin, which cover roughly 75 percent of the Earth's land surface, the discovery that bedrock nitrogen has the potential to stimulate forest productivity and carbon storage has tremendous global significance.
"The stunning finding that forests can also feed on nitrogen in rocks has the potential to change all projections related to climate change," said Houlton. "This discovery may also help explain several other studies that have found that the nitrogen 'budgets' of forests are out of balance, the nitrogen accumulation in their soil and plants being substantially greater than the apparent nitrogen inputs."
Houlton noted that nitrogen is becoming increasingly important in climate-change studies and researchers have begun to incorporate nitrogen in their climate-change models. Some models indicate that the nutrient could cause an additional increase in global temperatures of up to one degree Celsius (1.8 degrees Fahrenheit) by 2010, as it limits the amount of carbon dioxide that plants around the world can extract from the atmosphere. If more nitrogen is available than predicted from the traditional nitrogen-cycling pathways, as the UC Davis study suggests, it could lead to more carbon storage on land and less carbon remaining in the atmosphere.
The researchers call for further studies in other parts of the world to determine if nitrogen in rocks affects forests outside of the Pacific Northwest.
|Contact: Patricia Bailey|
University of California - Davis